Patent GB-990728-A (GB)
Title: Laminated sheet material
IPC: B32B27/00
Filed: 1960-05-13
Abstract: 990,728. Laminated sheet material. H. P. BARNS. Aug. 14, 1961 [May 13, 1960], No. 17O28/60. Addition to 850,791. Heading B5N. A laminated sheet material is produced by applying to a first sheet, which is disposed in a gaseous medium such as air, a substantially water-insoluble synthetic thermoplastic polymeric material by means of spraying or dusting so that the polymeric material adheres to the first sheet in the form of discrete separate particles, heat and if desired pressure being applied to make the particles adhere to the first sheet, the heat and pressure applied being not so great as to cause the discrete particles to coalesce into a continuous sheet or into large aggregates, laying against the first sheet a second sheet so that the discrete particles are between the two sheets and uniting the two sheets by heat and if desired pressure, one of the sheets being composed of foamed material such as foam rubber or foam plastics material. Both sheets may be porous and/or flexible, or composed of foamed material such as foam rubber or foam plastics material. One of the sheets may be a fabric, e.g. a cotton fabric. The thermoplastics polymeric material may have a softening point between 80‹ C. and 200‹ C. and may be polyethylene. The diameter of the particles may lie within the range 0.005 to 0.125 of an inch. The first sheet may be moved in its own plane upwardly at a small angle to the horizontal whilst the said particles are sprayed on to it from above. The first sheet maybe moved linearly in its own plane whilst the particles are dusted or sprayed on to it from a source of supply which is moved transversely of the direction of movement of the fabric. The polymeric material may be applied by dusting, one of the sheets being a fabric and the other being a sheet of foam material, and the heat is applied through the fabric. The first sheet may be heated before the discrete particles are applied. The polymeric material may be applied by dusting, the powder or granules are allowed to fall upon a moving sheet, or a container for the particles or granules moves or vibrates while the particles or granules are allowed to fall, or the heated sheet is vibrated or otherwise moved after the powder or granules have been deposited in order to cause the particles to assume their final discrete distribution. One of the sheets may be a fabric and the particles are deposited upon the other sheet through the meshes of the fabric so that both sheets receive discrete particles. The average distance between the discrete particles may be approximately three times the average diameter of the particles. The thermoplastic material has a heat-softening point which is lower than the heat-softening point or scorching point of either sheet. Examples of foamed material are polythene, polyvinyl chloride, polyvinyl acetate, natural or silicone rubbers, butadiene-methyl methacrylate, rubber modified phenolic resins and polyurethane, butadiene - styrene, rubberized polystyrene, polystyrene and its copolymers, phenolic and polyester resins. Specification 942,393 also is referred to.